The present invention relates generally to radiographic structural crack detection methods, and more particularly to standardized radiographs of simulated aluminum test specimens for training and testing radiographic interpreters.
Radiographic structural crack detection uses X-ray or gamma irradiation of structural components, generally aluminum aircraft components, to produce radiographs that can be examined and interpreted to reveal developing cracks. Accurate interpretation of radiographs is an acquired skill. Successful training of radiographic interpreters depends on the knowledge, patience and sight of a trainer, and the number of example cracks identified during training. Experience, in number, quality and variety, are critical to the successful training of a radiographic interpreter.
Unfortunately, there are no standardized training aids or visual accuracy test programs for radiographic interpreters. Old radiographs of actual aircraft components found in the field to have defects are not even generally saved to be used as examples because they can be recycled for their silver, and for other reasons. Even if some individual trainers or training sites have been able to accumulate individual collections of example radiographs for training and testing trainees, these individual collections suffer from lack of variety and consistency between collections, and the limited number of different radiographs in each collection makes it impossible to give functionally equivalent tests to individual trainees without the dishonesty risks inherent with having to test all the students using the same radiographs.
Complete training will require a greater number and variety of sample radiographs than are now available. Attempts to deliberately crack aluminum structural components to create the variety and number of radiographs needed for training has not proved successful in practice. An example of the need for more test sample radiographs is that, with the few test samples available, it is often difficult to make clear to a student how and why a false positive is not, in fact, a real defect and how to avoid such false positives in the future.
Thus it is seen that there is a need for a greater number and wider variety of radiographs suitable for training and testing radiograph interpreters than are now available.
It is, therefore, a principal object of the present invention to provide a method for making simulated aluminum plates having simulated structural defects that produce radiographic images that accurately mimic the radiographic image of an actual aluminum structural component with a selected defect.
It is another object of the present invention to provide a method for simulating blurring and non-relevant indications on a radiograph to provide better training and testing.
It is yet another object of the present invention to provide a means for certification of radiographic interpreters.
It is a feature of the present invention that a great variety of different structure defects can be simulated.
It is another feature of the present invention that a system of incrementally differing example radiographic images can be made to facilitate training.
It is an advantage of the present invention that it allows rapid weeding out of radiographic interpreting trainees who do not have good contrast discrimination.
It is another advantage of the present invention is that it allows use of expired X-ray film, thus reducing cost and waste.
It is a further advantage of the present invention that the simulated aluminum sheets are inexpensive and straightforward to make and use.
These and other objects, features and advantages of the present invention will become apparent as the description of certain representative embodiments proceeds.